[3.12] gh-83006: Document behavior of `shutil.disk_usage` for non-mounted filesystems on Unix (GH-107031)#107047

ambv merged 1 commit intopython:3.12python/cpython:3.12from

miss-islington:backport-6e5f223-3.12miss-islington/cpython:backport-6e5f223-3.12Copy head branch name to clipboard